Page 99 - 《高原气象》2025年第6期

6 期 陈霆炜等：青藏高原不同区域蒸散发变化特征及影响因子分析 1507

Analysis of Evapotranspiration Variation Characteristics and Influencing

Factors in Different Regions of the Tibetan Plateau

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CHEN Tingwei ， MA Yaoming 2， 1， 3， 4 ， XIE Zhipeng ， WANG Binbin ， ZUO Hongchao 1
（1. College of Atmospheric Sciences， Lanzhou University， Lanzhou 730000， Gansu， China；
2. Key Laboratory of Plateau Environmental Change and Surface Processes， Institute of Tibetan Plateau Research，
Chinese Academy， Beijing 100029， China；
3. University of Chinese Academy of Sciences， Beijing 100101， China；
4. China-Pakistan Earth Science Research Center， Chinese Academy of Sciences， Chengdu 610299， Sichuan， China）

Abstract： To investigate the long-term variation characteristics of actual evapotranspiration （ET） in different cli‐
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matic regions of the Qinghai-Xizang Plateau and its main influencing factors， as well as to enhance the under‐
standing of land-atmosphere interactions and eco-hydrological processes in the plateau region， this study selected
MAWORS， BJ， QOMS， and SETORS as representative observational sites. Based on long-term site observa‐
tions and satellite remote sensing data， the ET at different temporal scales was calculated for each site， and its
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correlation with meteorological factors was analyzed. Furthermore， a path analysis method was employed to
quantify the impact of environmental factors on daily ET during the monsoon season. The results showed that：
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（1） In terms of annual ET ， BJ exhibited the highest value， with a multi-year average of 592. 17 mm， followed
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by SETORS at 521. 34 mm. MAWORS ranked third， with an annual ET of 422. 84 mm， while QOMS had the
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lowest ET of only 206. 33 mm， significantly lower than the other sites.（2） Regarding the ratio of annual ET to
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precipitation， MAWORS had the highest value at 3. 34 due to its low precipitation. BJ followed with a ratio of
1. 11， while QOMS had a ratio of 0. 96， indicating a near balance in local water budget， with precipitation being
the primary water source for ET . SETORS exhibited the lowest ratio of 0. 68， suggesting a strong water retention
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capacity of the underlying surface， with a surplus of precipitation conducive to water resource accumulation and
vegetation growth.（3） The interannual variation trends showed that annual ET at MAWORS， BJ， and SETORS
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displayed an increasing trend. The increase at MAWORS was mainly attributed to the continuous enhancement of
net radiation， while the rise in BJ was closely related to an increase in soil moisture content. The upward trend at
SETORS was primarily driven by rising temperatures. In contrast， QOMS showed a decreasing trend in ET ，
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mainly due to a reduction in precipitation during the monsoon season.（4） ET at different sites was controlled by
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various environmental factors. At MAWORS， ET was primarily regulated by net radiation and soil moisture con‐
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tent， with glacier meltwater serving as a significant water source. At QOMS， where the terrain acts as a barrier
to water vapor transport， ET was predominantly controlled by precipitation， showing a clear water-limitation ef‐
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fect. At BJ， ET was jointly regulated by net radiation and soil moisture， with a stronger energy-limitation effect.
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At SETORS， abundant precipitation resulted in weak water limitations on ET ， making it mainly influenced by
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net radiation and temperature.（5） The regulatory effect of vegetation cover on ET was more evident at BJ and
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SETORS， whereas at MAWORS and QOMS， the correlation was weaker due to sparse vegetation.（6） During
the non-monsoon period， water vapor supply decreased significantly at all sites. Except for SETORS， soil at the
other sites remained frozen， with soil moisture content reaching its lowest level of the year. Consequently， the
ET process was mainly controlled by net radiation. At SETORS， where water vapor transport was reduced， ET
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relied more on precipitation supply.
Key words： Qinghai-Xizang Plateau； diurnal evapotranspiration； eddy covariance observation； path analysis